交流电气化铁道通信电磁防护的研究

研究目的:交流电气化铁路不仅对通信系统引起干扰,还会使电气化铁路附近的金属与导体间或金属导体与大地间产生感应电压而危及设备和人员安全,干扰通信设备正常工作。为保证通信安全,需要对电气化铁路对铁道通信的电磁影响和电磁防护进行研究,从而给铁路现场实际工作提供一定的理论依据。研究方法:本文利用电磁场对地下传输系统激励耦合的传输线方程及其一般解,建立了交流电气化铁路对地下传输系统干扰影响的分析方法。研究结果:研究得出了电气化铁路对铁道通信的影响机理,电气化铁路对铁道通信危险影响的限值,以及磁耦合影响、地电流影响和干扰影响计算公式,计算出了引起超限隔距数据。研究结论:电气化铁路的铁道通信电缆和铁道通信光缆电磁防护措施,可以有效地控制交流电气化铁路对铁道通信光、电缆的影响,达到电磁防护的目的。     

矩形贴片天线有限接地面对方向图的影响

讨论了一致性几何绕射理论（ＵＴＤ）的适用范围，并提出其适合于源离绕射边近的处理方法。在此基础上讨论了矩形贴片天线有限接地面的影响。数值结果与已发表的文献中的实验结果符合很好。     

Measuring the thicknesses of the freshwater-layer plume and sea ice in the land-fast ice region of the Mackenzie Delta using helicopter-borne sensors

Helicopter-borne sensors have been used since the early 1990s to monitor ice properties in support of winter marine transportation along the east coast of Canada. The observations are used in ice chart production and to validate ice hazard identification algorithms using satellite advanced synthetic aperture radar (ASAR) imagery. In this study we evaluated the sensors' additional capability to monitor the freshwater plume characteristic beneath land-fast ice. During the Canadian Arctic Shelf Exchange Study (CASES) data were collected over the Mackenzie Delta in the southern Beaufort Sea where a buoyant river plume exists. Results showed that the electromagnetic–laser system could describe not only the ice properties but also the horizontal distribution of the freshwater plume depths that decreased in depth stepwise offshore as the flow of the buoyant plume was restricted by a series of ridge-rubble fields running parallel to the coast. Relative to the 2 m mean ice thickness, the plume layer depth varied from zero under mobile offshore pack ice to 3 m inshore of the third set of ridge-rubble fields.     

管系湍流噪声辐射研究方法进展

从湍流声辐射的相关理论出发,介绍Lighthill声学比拟理论以及该理论的研究进展,如含固体边界的Curle方程、Powell的涡声理论等。运用这些理论,对潜艇舱室管路系统工作时,管道内及水阀内流体湍动引起的湍流边界层噪声、涡激噪声等进行机理性分析,对管系流动噪声的主要声源（包括偶极子源与四极子源）进行探讨,并列举工程上常用的管路噪声控制方法。     

便携式绝缘综合测试仪的研究

针对电气化铁道牵引供电设备的绝缘试验,研制了一种新型便携式绝缘综合测试仪。该测试仪具有利用计算机快速处理数据的能力和主动检测方法,并能有效地消除电磁干扰影响。研制中采用新型设计将高压源、调压装置等多种部件高度集成,其结构轻小,现场使用方便。     

O'ZBEKISTON型机车电磁兼容分析及处理

分析O'ZBEKISTON型交流传动电力机车的电磁兼容环境,并对其布线系统、控制系统、电源系统及信号系统的电磁兼容性进行处理。     

和谐HX_D1型机车主冷却塔风机驱动电机(JD280型)的设计

介绍HXD1型大功率交流电力机车主冷却塔风机用驱动电机(JD280型)的电磁设计和结构设计。在设计时首先考虑变频器特性及影响,同时分析了变频电机与普通工频电源供电电机设计时定子、转子槽形及绝缘结构上的差别。     

Variability of snow and ice thermal, physical and optical properties pertinent to sea ice algae biomass during spring

Changes in the thermal, physical and optical properties of the snow–sea ice system and feedbacks between various temporal and spatial scales affect accumulation of microalgae at the sea ice bottom and are the focus of this research. During the spring transition period, May 4 to June 9, 2002, we closely monitored atmospheric conditions and properties of the snow–sea ice system, including thermal, physical and optical properties of the snow cover (e.g., temperature, grain size, light attenuation), ice thickness and salinity, and biomass of bottom ice algae. Results show that snowdrift size averaged 31.2 by 10.6 m with a depth range of 2 to 45 cm. Snowpacks also varied in age, distinguished by coincident peaks of snow salinity and grain size and a lower PAR extinction coefficient. Spatial variability of the snowpack was superimposed by temporal variability associated with seasonal snow–ice melt and wind redistribution of snow. Maximum biomass of ice algae was observed under intermediate snow covers. Under thin snow covers, algae biomass declined steadily coincident with seasonal warming and desalination of the ice cover. Under thick snow covers, algae biomass was negatively correlated with snow depth. These results suggest that thin snow covers were associated with a thermal effect causing sloughing of algae, whereas under deep snow, algae were still light limited and thermally insulated from the warming atmosphere. Our results highlight the importance of snow cover history on the sea ice system operating below. Furthermore, in the context of current climate change scenarios, shifts in snow depth would result in decreases of ice algae biomass.     

“带动汽车专业建设、推进技工教育发展”汽车检测与维修专业群辐射推广研究

汽车检测与维修专业群建设是我院国家级汽车检测与维修实训基地建设的重点,是学校整体水平和办学特色的集中体现,关系到学校汽车检测与维修专业在全区示范引领作用,只有不断强化专业群建设,学校的长期生存和发展才有可靠保证。为整体提升专业群办学水平和人才培养质量,现从重点专业在专业群建设中的示范引领作用这一视角出发,阐述其在专业群建设中的独特作用。     

用波浪辐射动量应力分析波浪减水现象

从雷诺输运方程出发,推出动量流的应力张量表达式ρvivl,沿整个控制体的外表面做曲面积分(对坐标的曲面积分),得到的是一个合力,称为“辐射动量应力”.并将这种新计算方法求得的结果应用于求解波浪减水方程,与传统减水方程比较后得出:“辐射动量应力”不仅体现了“辐射应力”的本质特征,还拓展了辐射应力的适应范围.